Light comb generating device and spectrometers including same

Abstract

A light comb generating device according to a disclosed embodiment includes a light source for generating light in a reference wavelength band and outputting the generated light, and an optical comb generator for generating a light comb having a reference comb interval from the output light, wherein the light source changes a wavelength of the output light as much as a reference frequency interval for every reference time interval, the light comb is generated within a wavelength range of the reference frequency interval, and the reference wavelength band may be at least about 3 μm and no greater than about 30 μm.

What is claimed is: 
     
       1. A light comb generating device comprising:
 a light source configured to generate light in a mid-infrared wavelength band of at least about 3 μm and no greater than about 30 μm and to modulate and output the generated light; and 
 an optical comb generator configured to generate a light comb having a reference comb interval from the output light, 
 wherein the light source changes the wavelength of the output light stepwise as much as a reference frequency interval for every reference time interval, and the light comb is generated within a wavelength range of the reference frequency interval. 
 
     
     
       2. The light comb generating device of  claim 1 , wherein
 the light source comprises a diffraction grating, a beam deflector, and an optical gain medium, and 
 light generated by applying a current to the optical gain medium passes through the beam deflector and the diffraction grating, whereby the light in the mid-infrared wavelength band is generated. 
 
     
     
       3. The light comb generating device of  claim 1 , wherein the optical comb generator comprises a harmonic modulator configured to generate a harmonic wave of the light corresponding to a modulation frequency to change the reference comb interval. 
     
     
       4. The light comb generating device of  claim 3 , wherein the harmonic modulator comprises a Mach-Zender modulator which is a parallel combination of phase modulators. 
     
     
       5. A spectrometer comprising:
 a cell configured to fill a sample thereinto; 
 a light transceiver configured to transmit or receive light in a reference wavelength band; and 
 a dual optical comb generator configured to split the light received from the light transceiver into first light and second light, and generate a first light comb from the first light and generate a second light comb from the second light, wherein: 
 the dual optical comb generator comprises a distributor configured to separate the first light and the second light from the received light, 
 the first light comb and the second light comb respectively have a first frequency interval and a second frequency interval, the first light comb returns to the dual optical comb generator after passing through the cell, and 
 the dual optical comb generator transmits an optical signal in which the generated second light comb and the returned first light comb are combined. 
 
     
     
       6. The spectrometer of  claim 5 , wherein the reference wavelength band is at least about 3 μm and no greater than about 30 μm. 
     
     
       7. The spectrometer of  claim 5 , wherein the light transceiver comprises:
 a light source configured to generate the light in the reference wavelength band and outputting the generated light; and 
 a photodiode configured to convert the combined optical signal received from the dual optical comb generator into an electrical signal. 
 
     
     
       8. The spectrometer of  claim 7 , wherein
 the light source comprises a diffraction grating, a beam deflector, and an optical gain medium, and 
 light generated by applying a current to the optical gain medium passes through the beam deflector and the diffraction grating, whereby the light in the reference wavelength band is generated. 
 
     
     
       9. The spectrometer of  claim 5 , wherein the dual optical comb generator comprises:
 a first light comb generator configured to generate the first light comb from the first light; and 
 a second light comb generator configured to generate the second light comb from the second light. 
 
     
     
       10. The spectrometer of  claim 9 , wherein
 the first light comb and the second light comb respectively have a first reference comb interval and a second reference comb interval, 
 the first light comb generator comprises a first harmonic modulator configured to adjust the first reference comb interval, and 
 the second light comb generator comprises a second harmonic modulator configured to adjust the second reference comb interval. 
 
     
     
       11. The spectrometer of  claim 9 , wherein the dual optical comb generator further comprises a coupler configured to receive the generated second light comb and the returned first light comb, and combine the received second light comb and the first light comb to generate an optical signal. 
     
     
       12. The spectrometer of  claim 5 , wherein the cell comprises a gas tube in which the first comb proceeds. 
     
     
       13. The spectrometer of  claim 5 , wherein the combined optical signal is frequency-transformed, and absorbance or components of the sample is analyzed.